INJURIES BY ROUNDHEADED BORERS. 357 



The work of the insect is not confined to the large trees, but 

 straight young seedlings from 4 to 10 feet high are sometimes 

 attacked and the entire top taken off, resulting in the removal of 

 about 2 feet of the new growth, usually nearly two years' incre- 

 ment. The adult beetle apparently injures the smaller twigs by 

 feeding upon the bark without depositing eggs in them. 



Where this species occurs in destructive numbers it is advisable 

 to collect and burn the pruned twigs and branches. This should be 

 done several times between October 1 and August 1 of the following 

 year once just before the leaves fall, once early in the spring 

 before vegetation starts, and again in the summer during June or 

 July. The twigs which first fall are quite apt to be almost hidden 

 by fallen leaves and quite difficult to find in the spring. 



SUMMARY. 



Ill general, roundheaded borers are elongate, fleshy, yellowish- 

 white grubs, which hatch from eggs deposited by the parent beetles 

 in or upon the bark or wood of the host plant. The grubs finally 

 change to pupre and these in turn change to adults or beetles. The 

 young adults in time emerge from the host and deposit eggs in or 

 upon other host plants; and so the life cycle goes on. Usually there 

 is but one generation a year, but in some species there may be two 

 generations a year, and in other species it may take longer than a 

 year for a single generation to develop. 



Great damage is done to living and felled trees, and to standing 

 dead trees, by this class of borers. In some cases the borers confine 

 themselves to the bark, while in others they enter the wood. The 

 remedy in each case depends upon the habits and character of work 

 of the species under consideration. 



The western larch bark-borer attacks perfectly healthy western 

 larches, making winding, irregular galleries in the inner bark, thus 

 cutting off the flow of sap and killing the trees. The methods of 

 control are preventive. No attempt is made to save a tree which has 

 once become badly infested. After becoming infested, trees should 

 be felled and barked and the bark burned before the following 

 May 15. A few healthy trees felled in May or June, near those in- 

 fested, should attract the beetles which would otherwise deposit 

 eggs in healthy trees. Before the following spring the bark should 

 be stripped from these trap trees and burned. 



The southern pine sawyer is very destructive to felled pine timber 

 in the Southern States, making large, unsightly holes in the sap- 

 wood and greatly reducing in value a considerable percentage of 

 each log infested. Injury by this species may be prevented in two 

 ways. First, by placing infested logs in water while the larvse are 



